Method and apparatus for laying pipelines

ABSTRACT

A method and apparatus for laying a pipeline on a submerged surface from a vessel which is provided with one or more vessel propulsion units. Tension and lateral force exerted on the pipeline from the floating vessel are detected. The deviation of the vessel from a desired pipelaying course is also detected. The thrust effect of the vessel propulsion units is adjus

States i? aent Jones et ai.

[ 1 June 13, 1972 Filed:

METHOD AND APPARATUS FOR LAYING PIPELIN ES Jerry J. Jones; Delbert L. Keenon; William A. Morgan; Joe C. Lochridge, all of Houston, Tex.

Inventors:

Assignee: Brown & Root, Inc., Houston, Tex.

April 9, 1969 Appl. No.: 814,558

US. Cl. ..6l/72.3, 1 14/144, 235/ l 50.27 Int. Cl Fl6l 1/00, B63h 25/42 Field of Search... ....61/72.3, 72.4, 72.1; 114/144,

References Cited UNITED STATES PATENTS 7/l 968 Lawrence ..6l/72.3 10/1966 Shatto, Jr. etal ..114/144 12/1970 Kolb et al. ..6l/72.3

5/1971 Kolb ..235/l50.27

FOREIGN PATENTS OR APPLICATIONS 1,300,292 1962 I France ..114/235 Primary Examiner-Jacob Shapiro Attomey-Bums, Doane, Swecker & Mathis A method and apparatus for laying a pipeline on a submerged surface from a vessel which is provided with one or more vessel propulsion units. Tension and lateral force exerted on the pipeline from the floating vessel are detected. The deviation of the vessel from a desired pipelaying course is also detected.

ABSTRACT The thrust efi'ect of the vessel propulsion units is adjusted to insure that the desired tension is exerted on the pipeline. The vessel is also rotated to relieve lateral force interacting between the vessel and the pipeline. As a matter of subordinated priority, the thrust effect of the vessel propulsion units is adjusted in an effort to tend to restore the vessel to the desired or predetermined course and maintain the vessel on this course.

21 Claims, 24 Drawing Figures PATENTEDJUN 13 I972 3 668 878 sum 03 0F 14 KEENON WILLIAM A.

Zwm, 2mm, Emma,

Q Q a l 5 2% y 5m mm a an :EEUEE n55. :f w m? Lam .\A.| .1 [Ill W !i1l 3m w an I V ow e8 :8 73 1 8 8m Rm 2% mm B PATENTEUJUN 13 I972 3. 668.878

saw on or 14 FIG. 7

INVENTORS JERRY J. JONES DELBERT L. KEENON WILLIAM A. MORGAN JOE C. LOCHRIDGE um-r, 30m, Emma, 94ml Mat/14.;

ATTORN EYS PATENTEDJUH 13 1972 SHEET 05 [1F 14 INVENTORS JERRY J. JONES DELBERT L. KEENON WILLIAM A. MORGAN .105 c. LOCHRIDGE Fu w, 20m, maht, Made/ t /axhdr ATTORNEYS PATENTEDJUN 13 I972 sum 05 [1F 14 I j m INVENTORS JERRY J. JONES DELBERT L. KEENON WILLIAM A. MORGAN JOE C. LOCHRIDGE BY Bums, Dom, Bwm'ct, Jwectu Mum ATTORNEYS PATENTEUJUH 13 0972 8,668 878 SHEET 07 [1F 14 FIG. I?

INVENTORS JERRY J. JONES DELBERT L. KEENON WILLIAM A. MORGAN F JOE C. LOCHRIDGE Bur/u, 2mm, 22mm; $02M 2 Math:

ATTORNEYS PATENTEDJIIII I 3 I972 3, 668 8 7 8 SHEET 12 [1F 14 ACTUAL "NORMAL" H6, 20

INTERACTION BETWEEN STINGER 8 PIPELINE sa-a7 DES'RED NORMAL STINGER SEGMENTS INTERACTION BETWEEN BUOYANCY CONTROL STINGER a PIPELINE I I I |49b COMPUTER Y I?) STINGER SEGMENT JACKS ACTUAL STINGER I ATTITUDE DESIRED STINGER ATTITUDE TENSION (POUNDS) TIME , uwsmoas JERRY J. JONES DELBERT L. KEENON WILLIAM A. MORGAN JOE C. LOCHRIDGE BY ar/u; b0m,2md't, Tweeter 63 ATT mar,

PATENTEDJUN 13 I972 3, 668, 878

sum 130F111 FIG 23 HYE-NTORS JERRY J. JONES DELBERT L. KEENON WILLIAM A. MORGAN JOE C. LOCHRIDGE FIG. 22

BY Burns, Dom, 2mm be, Smear fl/at/uk' ATTORNEYS PATENTEDJUH 13 I972 sum in or 14 INVENTORS JERRY J. ES

DELBERT .EENO WILLIAM A. MORGA JOE C. LOCHRIDGE BY gums; boa/u Emma @decrer Mat 14" umrhn s METHOD AND APPARATUS FOR LAYING PIPELINES INDEX OF SPECIFICATION Column ABSTRACT OF DISCLOSURE ..Front GENERAL BACKGROUND l PRINCIPAL OBJECTS AND SUMMARY OF SUMMARY OF STRUCTURAL DETAILS OF STIN- GER AND CONNECTIONS BETWEEN STINGER SEGMENTS.. SUMMARY OF PRINCIPAL DETAILS OF STINGER LOAD SENSING SYSTEM 21 Vertical interaction 21 Lateral Interaction 23 Details and Variations in Interaction Monitoring... 23 SUMMARY OF NATURE OF VESSEL PROPUL- SION SYSTEM 24 MONITORING OF VESSEL POSITION 24 CONDITION SENSING PROGRAM........... 26 Moment or Lateral Force Monitoring 27 Tension Monitoring 27 Position Deviation Monitoring 28 Stinger Profile and Pivot Condition Monitoring..... 29 Mode of Condition Monitoring 29 DETERMINING OF THRUST CORRECTIONS... 29 Tension Deviation Calculation 29 Turning Moment or Lateral Interaction Calculatioh 31 Position Deviation Calculation 34 INTERACTION OF CORRECTIONS MINI- MIZED 36 Effect of Lateral Thrust, to Correct for Position Deviation, on Tension Correction 36 Effect of Turning Moment on Lateral Interaction and Tension Deviation 36 Effect of Tension and Position Deviation Corrections on Turning Moment 37 SUMMARY OF OVERALL CONTROL CON- CEPT 37 COMPUTERIZED SYSTEM FOR EFFECTING I NSJQ Y, LATERAEINIEEAQTIQN. AN VESSEL POSITION CORRECTIONS 40;

Computer Control Format 40 Computer Program Philosophy 42 STINGER CONTROL AUTOMATION 46 VESSEL AND PIPELINE SURVEILLANCE AND MANUAL CONTROL 47 Vessel Surveillance 48 Manual Control 50 SUMMARY OF PRINCIPAL ADVANTAGES AND OVERALL SCOPE OF INVENTION 51 GENERAL BACKGROUND In recent years, the continued exploitation of offshore oil and gas resources has required the laying of extensive pipeline networks for the purpose of collecting oil and gas from offshore wells and facilitating the transportation of the oil and gas to desired locations.

These offshore pipelaying operations are conducted on a world-wide basis. In many areas of the world, the pipelaying operations are conducted under extremely adverse environmental conditions. The effects of wind, waves, tide and currents, acting both on the pipelaying vessel and the pipeline being laid, tend to make it extremely difficult to lay a pipeline on a desired course while maintaining the stresses imposed on the pipeline during its laying within predetermined or acceptable stress limits.

In the past control has been maintained by utilizing winch operated anchor lines as a device for moving the pipelaying vessel forward, as pipelaying proceeds. With the pipelaying vessel under the control of the winch-operated anchor lines, an operator was able to maintain a reasonable degree of control over vessel position and rate of movement during the pipelaying operation.

However, technology has now developed to the point where ofi'shore drilling operations are being conducted in waters of such a depth as to make it difficult, and even impossible, to effectively control vessel position and movement through an anchor line system.

Thus, pipelaying operations in waters of extreme depth, i.e., on the order of 200 fathoms or greater, may, of necessity, rely upon the thrust exerted on a pipelaying vessel by vessel propulsion units.

Such vessel propulsion units are well known and may as sume a variety of forms. For example, the vessel propulsion units may comprise a plurality of fixedly positioned propeller or jet type vessel propulsion units disposed about the periphery of the hull. By varying the thrust level of individual propulsion units, desired changes in forward and lateral thrust exerted on the pipelaying vessel may be effected and desired turning moments may be imputed to the pipelaying vessel.

This control over the thrust effect exerted on a pipelaying vessel may be further enhanced by employing vessel propulsion units of the jet or propeller type which are movably mounted on the hull of the pipelaying vessel. With such movably mounted vessel propulsion units, both the level of thrust of the unit and the direction of thrust, i.e. azimuth, may be adjusted so as to make it possible for an operator or control system to adjust the thrust effect of an individual propulsion unit.

Vessel propulsion units of this general nature employed for the purpose of controlling vessel position are now known in the patent literature and described, for example, in such United States patents as: Wanzer, US. Pat. No. 2,987,027; Shatto, Jr. US. Pat. No. 3,176,645; Shatto, Jr. et al. U.S. Pat. No. 3,187,704; Beme US. Pat. No. 3,31 1,079; Goepfert et al. US. Pat. No. 3,214,921; Kolb et al. US. Pat. No. 3,145,683; Deal, Jr. et al. US. Pat. No. 3,228,368; and Cox et al. US. Pat. No. 3,331,212.

It has also been recognized, as a distinct advance in the pipelaying art, that the forces exerted on a pipeline in the direction of pipelaying may be monitored, with this monitoring being employed to control the thrust effect of vessel propulsion units. This concept is described, in a variety of for mats, in Lawrence US. Pat. No. 3,472,034 assigned to the assignee of the present invention.

The maintenance of tension control over a pipeline being laid on a submerged surface is contemplated in this aforesaid Lawrence US. Pat. No. 3,472,034, with a particularly efficacious mechanism for controlling tension being described in a Lawrence US. Pat. No. 3,390,532, also assigned to the assignee of the present invention. The tensioning apparatus featured in the aforesaid Lawrence US. Pat. No. 3,390,532 is particularly desirable as it provides a mechanism operable to continuously impart tension to a pipeline, with tension being maintained regardless of whether the pipelaying vessel is stationary relative to the pipeline, moving forward relative to the pipeline, or moving rearwardly relative to the pipeline. This tensioning mechanism is uniquely advantageous in that it provides a system for imparting tension to a pipeline, which tension is not significantly, adversely affected by wave action which tends to induce movement of the vessel relative to the pipeline in both forward and reverse directions.

Another singularly efiective technique for controlling the forces exerted on a pipeline during pipeline laying operations is described in a Rochelle et a1. U.S. Pat. No. 3,507,126 assigned to the assignee of the present invention.

These prior advances in the pipelaying art notwithstanding, there remains a significant, and hitherto unfulfilled, need for a dynamic vessel positioning concept which is uniquely geared to pipelaying operations and which is operable to effectively coordinate the maintenance of pipeline stress and pipeline position as pipelaying proceeds.

This need requires a unique assignment of priorities, with respect to the correcting of pipeline stresses relative to the position of a pipelaying vessel. It also requires the provision of a concept for monitoring vessel position with unique accuracy as pipelaying proceeds in deep waters, out of contact with conventional, land-based navigation control means.

Of particular significance is the need for a dynamic vessel positioning system which, unlike those featured in the aforesaid Wanzer, Shatto Jr., Shatto Jr. et aL, Goepfert, Kolb et al, Deal et al., and Cox et a]. patents, adequately compensates for the unique stop and go nature of offshore pipeline laying operations.

This stop and go characteristic results form the present day reliance upon welding as a system for lengthening the pipeline. This welding is effected on the pipelaying vessel and entails the addition of pipe joints or segments to a portion of the pipeline which is supported or gripped on the pipelaying vessel. The welding of the segments is conducted in stages. In general, the welding operation involves the more or less fixed gripping of the pipeline on the vessel, while adding a pipe joint or segment to the free extremity of the pipeline supported on the vessel. As a first weld is applied to the newly added segment to attach it to the pipeline, welded joints between previously added segments are strengthened at various welding stations spaced longitudinally along the pipeline on the pipelaying vessel. Periodically, welded segments of the gripped upper portion of the pipeline are allowed to feed downwardly toward the submerged pipeline portion.

The gripping of the upper portion of the pipeline during the welding or pipeline lengthening operation may be such as to accommodate some movement between the pipeline and the vessel as a result of wave action. Gripping of this nature, for example, is described in the aforesaid Lawrence U.S. Pat. No. 3,390,532.

This wave action induced, relative movement between the pipeline and vessel obviously presents complications with respect to the conducting of the welding operation. In deep, offshore waters where the wave action may be especially severe, the wave action induced movement between the pipeline and vessel may well be of such a magnitude as to make it difficult, if not impossible, to weld segments to the pipeline without resorting to complex welding stations which would be movable relative to the vessel and with the pipeline so as to minimize relative movement between a welder and the pipeline itself. While it may be feasible in certain instances to provide welding platforms which are more or less fixedly connected with a pipeline, so as to be movable relative to the pipelaying vessel, such platforms would be expected to consume desired working space and complicate the overall pipelaying operation.

Alternatively, positive gripping may be employed, intermittent with pipe segment feeding, so as to afiirmatively prevent movement of pipeline segments toward a submerged surface. Such a positive gripping arrangement is described in the aforesaid Lawrence U.S. Pat. No. 3,472,034. However, where such affirmative or positive gripping is employed, the action of waves, wind, tide, i.e. all environmental forces, acting on the pipelaying vessel may create a substantial problem in that these forces tend to produce significant changes in the level of tension imparted to the submerged portion of the pipeline from the gripped upper portion of the pipeline, fixedly secured on the pipelaying vessel.

Thus, the stop and go" nature of modern day pipelaying techniques creates certain problems with respect to relative movement between the pipeline and vessel and certain problems with respect to variations in force exerted on the pipeline. In addition, the stop and go" nature of offshore pipeline laying operations creates substantial problems with respect to the maintenance of the position of the pipelaying vessel on a desired course.

PRINCIPAL OBJECTS AND SUMMARY OF INVENTION It is a principal object of the invention to provide methods and apparatus for laying pipelines in offshore locations, where the stresses within (or force imposed on) the pipeline resulting from the pipelaying operation are effectively monitored and sought to be maintained within desired stress or applied force limits, and, as a subordinated priority, the position of the pipeline laying vessel is sought to be maintained on a desired course.

It is also a principal object of the invention to provide methods and apparatus for effecting the laying of pipelines in oflshore locations, which methods and apparatus effectively stabilize the upper portion of a pipeline gripped on a pipelaying vessel during segment welding or pipeline lengthening operations and concurrently insure that environmentally induced movement of the pipelaying vessel, transmitted to the stabilized upper portion of the pipeline, does not adversely affect the stresses in or forces acting on the pipeline.

It is another principal object of the invention to provide a unique pipeline feeding system by means of which a tensioning mechanism is employed to effect the feeding of pipeline segments from a pipelaying vessel without reliance upon the operation of vessel propulsion units.

Another object of the invention is to provide a composite system for imparting tension to a pipeline, in which composite system a pipeline gripping clamp is engaged with and freed from the pipeline under conditions so as to engender substantially no stress as a result of the engaging or disengaging operatron.

Another object of the invention is to provide a technique for determining deviations in pipeline tension, lateral interaction between the pipeline and stinger, and deviations in the course of the pipelaying vessel, and for determining appropriate corrections to be applied by vessel propulsion units at a frequency pattern which permits of the simultaneous correction for multiple deviation conditions.

Another object of the invention is to provide methods and apparatus for conducting ofishore pipeline laying operations where the operation of multiple, vessel propulsion units is controlled in a unique manner so as to tend to balance the operating loads of the vessel propulsion units.

It is also an object of the invention to provide methods and apparatus for determining the position of a pipelaying vessel, which methods and apparatus may employ an orbiting satellite as a means for detemiining vessel position, and wherein the satellite determined positions of the pipelaying vessel may be carried forward or extrapolated through reliance upon periodically repositioned navigation aids disposed generally along the pipelaying course.

A further object of the invention is to provide methods and apparatus for automating the control of a pipelaying vessel so as to properly and rapidly coordinate the corrections in vessel thrust required to maintain pipeline stresses and pipelaying vessel position within acceptable or predetermined limits.

It is also an object of the invention to provide a visual display of engine operating conditions which will facilitate manual superceding of a computer controlled, vessel propulsion system.

In describing the invention, reference will be made to a preferred embodiment.

This embodiment is characterized by a method of effecting the laying of a pipeline on a submerged surface from vessel means including a plurality of vessel propulsion units.

The method comprises the supporting of the pipeline from the floating vessel means so that an upper portion of the pipeline is supported from the floating vessel means and a generally submerged portion of the pipeline, connected with the upper portion extends downwardly to the submerged surface. At least periodically, at least an indication of a vector component of tension exerted on said pipeline from said floating vessel means is detected. At least periodically, at least an indication of a vector component of generally horizontally directed force interacting laterally between said floating vessel means and said pipeline and directed generally transversely of said pipeline is detected. At least periodically, at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means is detected. In response to this detecting of tension and interacting laterally directed force and the detecting of floating vessel means position and digital processing of this data (which permits a manual input of information relating thereto during the pipelaying operation), the thrust effect of the vessel propulsion units is adjusted to tend to maintain tension exerted on said pipeline generally within a predetermined tension range. The thrust effect of the vessel propulsion units is also adjusted to effect a turning movement of the floating vessel means, tending to maintain the interacting laterally directed force generally within a predetermined force range. In addition, the thrust effect of the vessel propulsion units is adjusted to tend to maintain the position of the floating vessel means generally on a desired course.

In a preferred embodiment, the supporting of the upper portion of the pipeline is effected by periodically gripping the upper pipeline portion so as to substantially prevent a segment of the upper portion from moving downwardly toward the generally submerged portion. In this preferred embodiment, periodically and alternately with the gripping of the upper portion of the pipeline, a segment of the upper portion is fed generally toward the generally submerged pipeline portion, while concurrently imparting a series of longitudinally spaced tensioning forces to the upper portion of the pipeline. These imparted tensioning forces are operable to continuously bias the upper portion of the pipeline in a direction tending to impart tension to the generally submerged pipeline portion. This biasing remains continuously in effect, substantially independent of the rate of vessel means movement and substantially independent of the direction of relative movement between the floating vessel means and the generally submerged portion of the pipeline.

Also in this preferred embodiment, and during the gripping of the upper portion of the pipeline, the level of tension imparted from the floating vessel means to the generally submerged portion of the pipeline is maintained at a tension level substantially above that maintained during the aforesaid segment feeding. This increase in tension tends to maintain the level of tension imparted to the generally submerged portion of the pipeline, during the aforesaid gripping, generally within an acceptable tension range, i.e., above a predetermined minimum tension level. This increase in tension imparted to the pipeline is intended to accommodate deviations in pipeline tension resulting from wave action or other environmental influences acting on the floating vessel means, without substantially deviating from a predetermined tension range.

This high tension level during pipeline gripping also serves a unique pipeline segment feeding function. When segment feeding is to be effected, a clamp gripping the pipeline is released and a yieldable tensioning device, possibly of the wheel-type, assumes the tensioning load. By reducing the tension inducing bias of the yieldable tensioning device, pipeline segments may be fed toward the submerged surface without relying on vessel propulsion unit induced, forward motion of the vessel means. With the tension being initially at a high level, it may be reduced for the segment feeding function without reducing tension below an acceptable lower limit.

In the preferred embodiment, periodically, a generally direct indication of tension exerted on the submerged portion of the pipeline is detected. Periodically, an indication of a vector component of generally horizontally directed force interacting laterally between the floating vessel means and the pipeline is detected. Periodically, an indication of any lateral displacement of the floating vessel means relative to a desired course of movement id detected.

In the preferred embodiment this detecting of vessel means position is effected by periodically determining the location of the floating vessel means with reference to an orbiting satellite. In this preferred embodiment, the periodically determined floating vessel means positions, determined by reference to the orbiting satellite, are extrapolated forward with reference to a generally fixedly positioned navigation station. Periodically, this station is relocated along the course of vessel movement.

In the preferred embodiment, and in response to the detecting of tension and interacting laterally directed force, and the detecting of floating vessel means position, the forces applied upon, i.e. the stresses within, the pipeline are maintained within acceptable limits as a first priority. Thereafter, as a second priority, a position correction is applied to the floating vessel means.

In the preferred embodiment, these corrections are effected by adjusting the thrust effect of the vessel propulsion units so as to tend to maintain tension exerted on the generally submerged portion of the pipeline generally within a predetermined tension range. In addition, the thrust effect of the vessel propulsion units is adjusted to exert a turning moment on the floating vessel means tending to maintain the interacting laterally directed force within a predetermined force range. Secondly, the thrust effect of the vessel propulsion units is adjusted to tend to maintain the position of the floating vessel means on a desired course.

In the preferred embodiment of the invention, the adjusting of the thrust effect of the vessel propulsion units, in relation to the tension correction, is effected so as to tend to maintain the deviation in thrust level between the vessel propulsion units within a predetermined format. This format may entail certain allowable ratios in vessel propulsion unit load levels, certain allowable differences in speed of these units, etc. In this preferred embodiment, the adjusting effect of the vessel propulsion units, with reference to the interacting lateral force, is effected by adjusting the thrust effect of the pairs of vessel propulsion units so as to tend to minimize translation of the floating vessel means and preferably also so as to maintain the deviation in thrust level between the vessel propulsion units within a predetennined format. Further, in this preferred embodiment, the adjusting of the thrust effect of the vessel propulsion units withrespect to the course or position correction is effected so as to tend to maintain the deviation in thrust level between the vessel propulsion units within a predetermined format.

The invention, of course, contemplates various unique combinations of apparatus means for implementing the individual and collective aspects of the foregoing methods.

The invention also contemplates a novel dynamic correction approach wherein the thrusts of vessel propulsion units are adjusted taking into account detecting deviation, environmental bias, and rate of deviation.

DRAWINGS In describing the invention, reference will be made to a preferred embodiment shown in the appended drawings.

In the Drawings:

FIG. 1 provides a side elevational view of floating vessel means (including a pipelaying barge and a buoyant and articulated ramp or stinger which is pivotably connected to the barge and depends downwardly toward a submerged surface), a pipeline tensioning and pipeline clamping assembly mounted on the barge and operable to restrain the upper portion of the pipeline, and the pipeline itself extending from the barge down to the ocean floor or submerged surface;

FIG. 2 provides a detailed side elevation view of the pipe tensioning mechanism illustrated schematically in FIG. 1;

FIG. 3 provides a top plan view of the pipe tensioning mechanism shown in FIG. 2;

FIG. 4 provides a transverse sectional view of the FIG. 2 pipe tensioning mechanism, as viewed along the section line 44 of FIG. 3;

FIG. 5 provides a partially sectioned, side elevational view,

as viewed along section line 5 of FIG. 6, looking toward the port side of the FIG. 1 assembly, of a pipe clamp which is incorporated on the deck of the pipelaying barge of FIG. 1, and positioned aft of the pipe tensioning mechanism illustrated in FIGS. 2 through 4;

FIG. 6 provides a partially sectioned, end elevational view of the FIG. 5 clamping mechanism, as viewed along the section line 66 of FIG. 5;

FIG. 7 provides a perspective exploded-format view of hitch components of the barge and upper end of the stinger, by means of which the stinger is pivotally attached to the stern of the barge;

FIG. 8 provides a perspective view of adjacent segments of the articulated stinger which are interconnected by hinge and jacking mechanisms for limited vertical articulation and locking;

FIG. 9 provides a side elevational view of the hinge and jacking mechanism interposed between the stinger segments, shown in fragmentary form in FIG. 8;

FIG. 10 provides a perspective view of the lower or outermost segment of the articulated stinger, illustrating the general disposition of sensing devices operable to detect both vertically and laterally directed interacting forces between the pipeline and the stinger portion of the pipelaying vessel means;

FIG. 11 provides a top plan, fragmentary view of the load sensing stinger segment shown in FIG. 10;

FIG. 12 provides a fragmentary, top plan view of a representative side load sensing unit incorporated in the port side of the outermost stinger segment of FIG. 10;

FIG. 13 provides a fragmentary, side elevational view of the representative, lateral load detecting unit shown in FIG. 12, viewing this load cell generally from the cradled or longitudinally centered location of the pipeline;

FIG. 14 provides a generally vertically sectioned, fragmentary view of a representative vertical load measuring cell incorporated in the outermost stinger segment of FIG. 10, as viewed generally along the section line 1414 of FIG. 11;

FIG. 15 provides a schematic illustration of the hull of the FIG. 1 pipelaying barge, illustrating the general location of vessel propulsion units in relation to the barge hull and the articulated stinger, viewing these locations in a top plan view format;

FIG. 16 provides a schematic representation in top plan view format of the lay barge and stinger, illustrating the detected deviations in tension and lateral force and detected deviation in course position, and also illustrating the resultant forces which are to be applied to the lay barge to tend to eliminate such deviations;

FIG. 17 provides a diagrammatic representation of the manner in which parameters affecting the pipelaying operation are detected, and appropriate corrective action taken;

FIG. 18 provides a schematic illustration of a computerized, servocontrol system employed to effect adjustments in the thrust effect of the propulsion units of the FIG. 1 pipelaying barge, in response to the detection of deviations in pipeline stresses and in lay barge position;

FIG. 19 schematically represents the steps involved in a computerized control system intended to optimize the advantages of the invention;

FIG. 20 provides a diagrammatic representation, indicating the manner in which the normal force acting generally perpendicularly between the outermost stinger segment and the pipeline may be monitored and employed to insure the continued conforming or supporting engagement between the stinger and the pipeline;

FIG. 21 schematically illustrates the manner in which the tension vectors of the vessel propulsion units are adjusted in an effort to maintain pipeline stress within acceptable limits;

FIG. 22 depicts the manner in which the thrust and azimuth of the vessel propulsion units are adjusted in an effort to maintain the forces acting on the pipeline and the position of the lay barge within acceptable limits;

FIG. 23 illustrates the manner in which the thrust and azimuth of an individual vessel propulsion unit are adjusted in the FIG. 22 representative, showing corrective vectors applicable to offset tension, lateral interaction, and course deviations; and

FIG. 24 graphically illustrates a control console which is intended to provide the operator of the lay barge with efiective monitoring of the overall pipeline operation.

PRINCIPAL COMPONENTS OF THE PIPELAYING SYSTEM FIG. 1 schematically illustrates a pipelaying operation, depicting the laying of a pipeline 1 on a submerged surface 2.

The pipeline 1 includes a lower, generally submerged portion 3 which extends upwardly from the ocean floor or submerged surface 2 to an upper portion 4 which is supported from floating vessel means 5. Vessel means 5 is provided with vessel propulsion means, comprising a plurality of individually controllable vessel propulsion units 6. Portions 3 and 4 of pipeline 1 are, for the purpose of this discussion, viewed as zones of the pipeline profile which translate along the pipeline as it is laid.

A portion 3a of the submerged pipeline portion 3 constitutes the portion already fully laid on the submerged surface 2. As illustrated, pipeline portion 3a may extend from an offshore tower or derrick-like installation 7. Installation 7 may comprise, for example, a collecting or tanker loading station or a well provided with a riser conduit 8. Riser conduit 8 extends from L-shaped junction 8a, where riser 8 and pipeline segment 3a are joined, to appropriate fluid handing means 9 supported by the tower or derrick 7 above the water surface or waterline 10.

One manner in which the laying of the pipeline 3 may be initiated away from the installation 7 is generally described, for example, in a Broadway et al. U.S. Pat. No. 3,258,928, assigned to the assignee of the present invention. However, as will be appreciated, this invention commences from the point after the initial part of pipeline portion 3a has been positioned.

Floating vessel means 5 may be considered as comprising a pipelaying vessel 11 upon which the propulsion units 6 are mounted. Pipelaying vessel 11 is provided, on the underside of its hull, with a plurality of peripherally dispersed, engine propulsion units 6. It is contemplated, by way of example, that six such engine propulsion units may be provided, each being a right angle drive or cycloidal type unit adjustable both as to thrust azimuth and thrust level. It is contemplated that each unit may have a capacity at least on the order of 1,500 horsepower.

Floating vessel means 5 also comprises a buoyant ramp or stinger" assembly 12. Stinger assembly 12 is attached to vessel 11 for vertical pivot movement and serves to provide support to the underside of the pipeline portion 3 during the initial portion of the descent of pipeline segments from the floating vessel means 5, downwardly toward the submerged surface 2.

While stinger 12 may assume a variety of forms, the present invention contemplates the use of a generally rigid, buoyant stinger which may be articulated or adjustable in profile, in a generally vertical direction, but which is more or less fixedly positioned with respect to the lay vessel 11 insofar as generally horizontal movement is concerned. With the stinger 12 more or less rigidly mounted on the vessel 11, insofar as horizontal movement is concerned, the stinger l2 and vessel 11 may be considered as unitary or horizontally non-articulated floating vessel means 5.

In the preferred embodiment, the articulated stinger 12 will comprise a plurality of buoyant segments 13. Adjacent buoyant segments 13 are pivotally interconnected by hinge means 14 having a generally horizontal pivot axis. The degree of inclination between adjacent segments 13 may be selectively adjusted and locked in place by mechanical or hydraulic jack units 15. Preferably these units are of the screw jack variety.

The operation of the jack means 15, for the purpose of adjusting and locking inclination between segments 13, may be effected remotely from the barge 11 or may be effected by divers at the location of each individual jack unit 15. Similarly, the buoyancy of each segment 13 may be adjusted remotely from the lay barge 11, or alternatively may be adjusted by divers operating flooding and air valves associated with each individual segment 13.

Structural details of the articulated stinger are generally described in the aforesaid Rochelle et al. U.S. Pat. No. 3,507,126, the disclosure of which is herein incorporated by reference.

Representative systems for adjusting the buoyancy of individual segments 13 are described in detail in the aforesaid Rochelle application. This Rochelle disclosure, with respect to buoyancy, embodies, in principal, the buoyancy control'disclosures exemplified by the teachings of the aforesaid Lawrence'US. Pat. No. 3,390,532 and an earlier Hauber et al. U.S. Pat. No. 3,280,571, also assigned to the assignee of the present invention and the disclosures of which are herein incorporated by reference.

The outermost stinger segment 13a, positioned at the lower stinger extremity, is provided with load cells for measuring the normal interaction, between the pipeline portion 3 and the portion of the floating vessel means 5 defined by the stinger l2, i.e. the interaction in a generally vertical, longitudinal median plane of the pipeline, directed generally perpendicular to the pipeline central axis at the load cell site. Segment 13a is also provided with load cell means for detecting the laterally interacting force between the portion of the vessel means 5 defined by the stinger l2 and the pipeline portion 3. This laterally interacting force is directed generally horizontally and transversely of the longitudinally extending and generally vertically extending, median plane P of the barge 11, shown, for example, in FIG. 15. This median plane P is parallel to the generally vertical, longitudinally extending median plane of the stinger 12. At this point, it will be recognized that the terms horizontal and vertical are used with reference to calm sea conditions where essentially no wave action is in evidence.

Load cells associated with the segment 13a for the purpose of detecting both vertically and laterally directed forces imposed onthe pipeline portion 3 are described in detail in the aforesaid Rochelle et al. U.S. Pat; No. 3,507,126, the disclosure of which is incorporated herein by reference. Details of presently preferred and modified forms of these load cells will be subsequently described in this disclosure.

The stinger 12 is connected by a hitch unit 16 to the stern of the lay vessel 11. Hitch unit 16 connects the stinger 12 to the vessel 11 so as to permit generally vertical pivotal movement of the stinger 12 relative to the vessel 11 about a generally horizontally directed pivot axisIThe hitch unit l6connects the stinger 12 to the vessel 11 so that the stinger l2 defines a pipeline support, constituting a longitudinal continuation of a pipeline supporting ramp 17 formed on the starboard side of the vessel 11. Ramp l7 inclines, in an aft direction, toward water surface 10. obviously, ramp 17 and stinger 12 could be so aligned at locations other than a side of vessel means 5.

Structural details of the hitch 16, which will be subsequently briefly reviewed, are generally set forth in detail in the disclosure of Lochridge et al. U.S. Pat. No. 3,538,712, assigned to the assignee of the present invention. The disclosure of this Lochridge et al. application is herein incorporated by reference with respect to the hitch unit 16.

The manner in which the pipelaying ramp 17 and the stinger 12 are provided with pipe cradling rollers so as to provide a friction-easing and cradling support of the pipeline segments as they move from the upper portion 4 toward the portion 3b, suspended between the outer extremity of the stinger 12 and the ocean floor 2, is described in detail in the aforesaid Lawrence U.S. Pat. No. 3,390,532 as well as in the aforesaid Hauber et al. U.S. Pat. No. 3,280,571.

Lay barge 11 is provided with a yieldable, pipe tensioning or biasing unit 18. A periodically operable pipe clamping unit 19 is mounted on the lay barge 11 and may be located aft of the tensioning unit 18 and between the tensioning unit 18 and the stinger 12. It isalso feasible for clamping unit 19 to be located forward of tensioner unit 18.

Tensioner 18 comprises a torqued-wheel type tensioner unit of the type described in detail in the aforesaid Lawrence U.S.

Pat. No. 3,390,532, the disclosure of which is herein incorporated by reference. This tensioning unit is uniquely operable to impart continuous, tension inducing bias to the pipeline, with this tension remaining in effect regardless of vessel movements induced by environmental forces such as wave action. This wave action may cause the vessel 11 to undergo movement generally toward the submerged portion 3 or away from the portion 3. Even during such movement, and even while the vessel 11 is stationary at any particular location, the tensioning mechanism 18 continues to effectively bias the pipeline upper portion 4 so as to apply tension to the generally submerged portion 3. This tension, which may be varied to induce feeding of pipeline segments, is significant in that it prevents buckling of the suspended free zone 3b of the pipeline portion 3, extending from stinger 12 to surface 2, and may be adjusted to prevent undesired movement of the pipeline segments along the ramp l7 and stinger 12 toward the submerged surface 2.

The tensioning mechanism 18 serves to apply tension to the pipeline while the vessel means 5 is stationary, moving ahead or moving rearwardly along the pipelaying course. Thus, during the paying out or feeding of pipeline segments aft of the vessel means 5, continuous, albeit possibly varied, tension is maintained.

Interrnittently or alternately with the paying out or feeding of segments of the pipeline, the pipeline upper portion 4 is more or less rigidly clamped by clamping mechanism 19, to be subsequently described. The clamping mechanism 19 generally fixedly secures the pipeline upper portion 4 relative to the lay barge 11 so as to prevent movement of the upper pipeline portion 4 relative to the deck and ramp 17 of the lay barge (except for the generally undiscernible movement permitted by tension load measuring means associated with unit 19). This immobilization of the pipeline relative to the lay barge enables the pipeline lengthening or welding operation to be conducted, unhampered by relative movement between the pipeline and the lay barge.

In a manner to be subsequently described in detail, the clamping mechanism 19 engages the pipeline portion 4 while it is being tensioned by the mechanism 18. Preferably before this engagement, the tensioning level of mechanism 18 is elevated. This elevation, or raising, of the tensioning level applied to the pipeline serves to stop the feeding of pipeline segments toward the submerged surface. This intensified or elevated tensioning level is applied at a level to accommodate, during the clamping of pipeline by gripping unit 19, for changes in tension which would result from wave action acting on the vessel means 5, and to permit subsequent feeding of pipeline segments by mechanism 18 when clamping unit 19 is disengaged from the pipeline. Thus, with the clamping mechanism 19 clamped to the pipeline portion 4, and with the higher level of tension being applied by either or both of units 18 and 19, movement of the lay vessel 11 generally toward the submerged portion 3 of the pipeline, as a result of wave action or other environmental forces, will not reduce the level of applied tension below a predetermined or acceptable level. Further, with unit 19 disengaged, pipeline segments may be fed toward surface 2 merely by reducing the tension level of unit 18.

Before proceeding with a discussion of the manner in which deviation in acceptable pipeline stress and deviation in lay vessel course position are detected and sought to be corrected, it is believed desirable to summarize certain structural aspects of the components of the pipelaying system heretofore outlined.

SUMMARY OF STRUCTURAL DETAILS OF TENSIONING MECHANISM FIGS. 2, 3 and 4 illustrate structural details of the tensioning mechanism 18 which is mounted on the pipelaying ramp 17 of the lay barge 1 1.

As illustrated, mechanism 18 comprises first frame means 20 and second frame means 21. The second frame means 2 1 is fixedly mounted on the ramp 17. Columns 22 and 22a telescopingly receive and movably mount the first frame 

1. A method of effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said method comprising: supporting a pipeline from said floating vessel means so that an upper portion is supported from said floating vessel means, and a generally submerged portion, connected with said upper portion, extends downwardly to said submerged surface; at least periodically, detecting at least an indication of a vector component of tension exerted on said pipeline from said floating vessel means; at least periodically, detecting at least an inDication of a vector component of force interacting laterally between said floating vessel means and said pipeline and directed generally transversely of said pipeline; at least periodically, detecting at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means; and digitally processing said indication of tension exerted on said pipeline from said floating vessel means, indication of force interacting laterally between said floating vessel means and said pipeline, and indication of the position of said floating vessel means relative to a desired course of movement in accordance with a predetermined digital computer program; in response to said digital processing of said indications of tension and interacting laterally directed force and said detecting of said indication of floating vessel means position, adjusting the thrust effect of said vessel propulsion units to tend to maintain tension exerted on said pipeline generally within a predetermined tension range, adjusting the thrust effect of said vessel propulsion units to effect a movement of said floating vessel means tending to maintain said interacting laterally directed force generally within a predetermined force range, and adjusting the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means generally on a desired course; effecting said adjusting of the thrust effect of said vessel propulsion units to effect a movement of said floating vessel means tending to maintain said interacting laterally directed force within a predetermined force range as a matter of first priority in relation to thrust available from said vessel propulsion units; effecting said adjusting of the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means on said desired course as a matter of second priority in relation to, and to the extent permitted by, thrust available from said vessel propulsion units; at least at times, simultaneously effecting all of said adjustings of the thrust effects of said vessel propulsion units so as to tend to simultaneously maintain tension exerted on said pipeline generally within said predetermined tension range, maintain said interacting laterally directed force generally within said predetermined force range, and maintain the position of said floating vessel means generally on said desired course; inducing said adjustings of the thrust effects of said vessel propulsion units at values derived at least in part from a magnitude of deviation, and a bias tending to produce said deviation in relation to each of predetermined values of tension in said pipeline, force interacting laterally between said pipeline and said floating vessel means, and floating vessel means position; and during said laying of said pipeline, maintaining said digital computer program operable to receive digital processing data which is independent of said detected indications of tension, interacting laterally directed force, and position of said floating vessel means, and which relates to at least one of said predetermined tension range, said predetermined range of interacting laterally directed force, and said desired course of movement of said floating vessel means.
 2. A method of effecting the laying of a pipeline on a submerged surface from vessel means including a plurality of vessel propulsion units, said method comprising: supporting a pipeline from said floating vessel means so that, an upper portion is supported from said floating vessel means, and a generally submerged portion, connected with said upper portion, extends downwardly to said submerged surface; said supporting of said upper portion of said pipeline being effected by periodically gripping said upper portion of said piPeline so as to substantially prevent a segment of said upper portion from moving downwardly toward said generally submerged portion, periodically and alternately with said gripping of said upper portion of said pipeline, feeding segments of said upper portion of said pipeline generally toward submerged portion of said pipeline during said gripping accommodating deviations in pipeline tension resulting from environmental forces acting on said floating vessel means without substantially deviating from a predetermined pipeline tension range; intermittently with said gripping, reducing the tension imparted to said pipeline to thereby cause said feeding of segments; at least periodically, detecting at least an indication of a vector component of tension exerted on said submerged portion of said pipeline from said floating vessel means; at least periodically, detecting at least an indication of a vector component of generally horizontally directed force interacting laterally between said floating vessel means and said submerged portion of said pipeline and directed generally transversely of said pipeline; at least periodically, detecting at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means, said detecting being effected by periodically determining the location of said floating vessel means with reference to an orbiting satellite orbiting the earth, between the periodic determining of floating vessel means position with reference to said orbiting satellite, extrapolating the position of said floating vessel means with reference to a generally fixedly positioned and submerged navigation station, and periodically repositioning said submerged navigation station along said course of movement of said vessel means in response to said detecting of said indications of tension and interacting laterally directed force and said detecting of said indication of floating vessel means position as a matter of first priority, adjusting the thrust effect of said vessel propulsion units to tend to maintain tension exerted on said generally submerged portion of said pipeline generally within a predetermined tension range, and adjusting the thrust effect of said vessel propulsion units to effect a turning movement of said floating vessel means tending to maintain said interacting laterally directed force within a predetermined force range, and as a matter of second priority adjusting the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means on a desired course; effecting said adjusting of the thrust effect of said vessel propulsion units, tending to maintain the tension exerted on said submerged portion of said pipeline generally within a predetermined tension range, so as to tend to maintain the deviation in thrust level between said vessel propulsion units within a predetermined condition of balance; effecting said adjusting of the thrust effect of said vessel propulsion units, tending to maintain interacting lateral force between said floating vessel means and said submerged portion of said pipeline generally within a predetermined force range, by adjusting the thrust effect of pairs of vessel propulsion units so as to tend to minimize translation of said floating vessel means and so as to tend to maintain the deviation in thrust level between said vessel propulsion units within said predetermined condition of balance; and effecting said adjusting of the thrust effect of said vessel propulsion units, tending to maintain said floating vessel means generally on a desired course, so as to tend to maintain the deviation in thrust level between said vessel propulsion units within said predetermined condition of balance.
 3. A method of effecting the laying of a pipeline on a submerged surface from vessel means including a plurality of vessel propulsion units, saiD method comprising: supporting a pipeline from said floating vessel means so that, an upper portion is supported from said floating vessel means, and a generally submerged portion, connected with said upper portion, extends downwardly to said submerged surface; said supporting of said upper portion of said pipeline being effected by periodically gripping said upper portion of said pipeline so as to substantially prevent a segment of said upper portion from moving downwardly toward said generally submerged portion, periodically and alternately with said gripping of said upper portion of said pipeline, feeding segments of said upper portion of said pipeline generally toward said generally submerged portion of said pipeline while concurrently imparting a series of longitudinally spaced tensioning forces to said upper portion of said pipeline operable to continuously bias said upper portion of said pipeline in a direction tending to impart tension to said generally submerged portion of said pipeline with said biasing being imparted by pneumatically inflated rotary tires and remaining continuously in effect, substantially independent of the rate of floating vessel means movement and substantially independent of the direction of relative generally submerged portion of said pipeline, movement between said floating vessel means and said generally submerged portion of said pipeline, concurrently with said gripping, cradling said upper portion of said pipeline with said rotary tires to prevent lateral displacement thereof, during said gripping of said upper portion of said pipeline, adding pipeline segments to said upper portion and providing a level of tension imparted from said floating vessel means to said generally submerged portion of said pipeline at a tension level substantially above that maintained during said feeding of pipeline segments so as to tend to maintain the level of tension imparted to said generally submerged portion of said pipeline during said gripping generally within a tension range which accommodates deviations in tension resulting from environmental forces acting on said floating vessel means without substantially deviating from a predetermined tension range; and intermittently with said gripping, causing said rotary tires to reduce said tensioning level and thereby cause said feeding of pipeline segments; at least periodically at a first detection frequency and concurrent with said gripping, detecting at least an indication of a vector component of tension exerted on said submerged portion of said pipeline from said floating vessel means; at least periodically at a second detection frequency equal to or less than said first detection frequency, and concurrent with said gripping, detecting at least an indication of a vector component of generally horizontally directed force interacting laterally between said floating vessel means and said submerged portion of said pipeline and directed generally transversely of said pipeline; at least periodically at a third detection frequency equal to or less than said second detection frequency, and concurrent with said gripping detecting at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means, said detecting being effected by periodically determining the location of said floating vessel means with reference to an orbiting satellite, between the periodic determining of floating vessel means position with reference to said orbiting satellite and concurrent with said gripping, determining the position of said floating vessel means with reference to a generally fixedly positioned and submerged sonar beacon means, and periodically repositioning said submerged navigation station means along said course of movement of said vessel means and extrapolating the position of said floating vessel means with reference to said sonar beacon means; in response to said detecting of said Indications of tension and interacting laterally directed force and said detecting of said indication of floating vessel means position, as a matter of first priority, adjusting the thrust effect of said vessel propulsion units to tend to maintain tension exerted on said generally submerged portion of said pipeline generally within a predetermined tension range; and adjusting the thrust effect of said vessel propulsion units to effect a turning movement of said floating vessel means tending to maintain said interacting laterally directed force within a predetermined force range, and as a matter of second priority, adjusting the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means on a desired course; effecting said adjusting of the thrust effect of said vessel propulsion units, tending to maintain the tension exerted on said submerged portion of said pipeline generally within a predetermined tension range, so as to tend to maintain the deviation in thrust level between said vessel propulsion units within a predetermined condition of balance; effecting said adjusting of the thrust effect of said vessel propulsion units, tending to maintain interacting lateral force between said floating vessel means and said submerged portion of said pipeline generally within a predetermined force range, by adjusting the thrust effect of pairs of vessel propulsion units so as to tend to minimize translation of said floating vessel means and so as to tend to maintain the deviation in thrust level between said vessel propulsion units within said predetermined condition of balance; effecting said adjusting of the thrust effect of said vessel propulsion units, tending to maintain said floating vessel means generally on a desired course, so as to tend to maintain the deviation in thrust level between said vessel propulsion units within said predetermined condition of balance; and effecting said adjusting of said thrust effects of said vessel propulsion units tending to maintain the tension exerted on said submerged portion of said pipeline generally with a predetermined range, tending to maintain interacting lateral force between said floating vessel means and said submerged portion of said pipeline generally within a predetermined force range, and tending to maintain said floating vessel means generally on a desired course, so that at least on a cyclic basis, a plurality of said thrust effects are generally simultaneously adjusted.
 4. A method of effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said method comprising: supporting a pipeline from said floating vessel means so that, an upper portion is supported from said floating vessel means, and a generally submerged portion,connected with said upper portion, extends downwardly to said submerged surface; said supporting of said upper portion of said pipeline being effected by: periodically gripping said upper portion of said pipeline with clamping means so as to substantially prevent a segment of said upper portion from moving downwardly toward said generally submerged portion, and periodically and alternately with said gripping of said upper portion of said pipeline, utilizing tensioning means to feed segments of said upper portion of said pipeline generally toward submerged portion of said pipeline; during said feeding of pipeline segments imparting yieldable tension with said tensioning means to side means of said upper portion of said pipeline on said floating vessel means; initiating said feeding of pipeline segments by reducing the level of tension imparted to said side means of said upper portion of said pipeline by said tensioning means, substantially independent of force exerted on said vessel means by said vessel propulsion means, with said reducing of tension being operable to cause feeding of a segment of said pipeline frOm said upper portion generally toward said generally submerged portion; and during said feeding of pipeline segments, increasing the level of tension imparted to said side means of said upper portion of said pipeline by said tensioning means, substantially independent of force exerted on said vessel means by said vessel propulsion means, with said increasing of tension being operable to substantially prevent the feeding of further segments of said pipeline from said upper portion of said pipeline generally toward said generally submerged portion; during said gripping of said upper portion of said pipeline with clamping means, adding pipeline segments to said upper portion of said pipeline and providing a level of tension imparted from said floating vessel means through said support means to said generally submerged portion of said pipeline at a tension level substantially above that maintained during said feeding of pipeline segments so as to tend to maintain the level of tension imparted to said generally submerged portion of said pipeline during said gripping generally within a tension range which accommodates deviations in tension resulting from environmental forces, including wave action, acting on said floating vessel means without deviating from a predetermined tension range.
 5. A method of effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said method comprising: supporting a pipeline from said floating vessel means so that, an upper portion is supported from said floating vessel means, and a generally submerged portion, connected with said upper portion, extends downwardly to said submerged surface; detecting a deviation in the condition of said pipeline; digitally processing said indication of a deviation in the condition of said pipeline in accordance with a predetermined digital computer program; in response to said digital processing, adjusting the thrust effect of said vessel propulsion means in an effort to tend to relieve said detected deviation, with said adjustment in thrust effect including a first component which is related directly to and tends to offset said detected condition of deviation, a second component which tends to offset a bias condition tending to produce said deviation, and a third component which tends to offset the rate at which said deviation occurred; effecting said adjusting of the thrust effect of said vessel propulsion means to tend to relieve said detected deviation in the condition of said pipeline as a matter of first priority in relation to thrust available from said vessel propulsion means; effecting an adjusting of the thrust effect of said vessel propulsion means to tend to maintain the position of said floating vessel means on a desired course as a matter of second priority in relation to, and to the extent permitted by, thrust available from said vessel propulsion means; and during said laying of said pipeline, maintaining said digital computer program operable to receive digital processing data which is independent of said detected deviation in the condition of said pipeline and which relates to said pipeline condition.
 6. A method of effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said method comprising: supporting a pipeline from said floating vessel means so that an upper portion is supported from said floating vessel means, and a generally submerged portion, connected with said upper portion, extends downwardly to said submerged surface; at least periodically, detecting at least an indication of a vector component of tension exerted on said pipeline from said floating vessel means; at least periodically, detecting at least an indication of a vector component of generally horizontally directed force interacting laterally between said floating vessel means and saId pipeline and directed generally transversely of said pipeline; at least periodically, detecting at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means; in response to said detecting of said indications of tension and interacting laterally directed force and said detecting of said indication of floating vessel means position, adjusting the thrust effect of said vessel propulsion units to tend to maintain tension exerted on said pipeline generally within a predetermined tension range, adjusting the thrust effect of said vessel propulsion units to effect a turning movement of said floating vessel means tending to maintain said interacting laterally directed force generally within a predetermined force range, and adjusting the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means generally on a desired course; displaying, on floating vessel means, a visual representation of thrust azimuth means of said vessel propulsion means; and operating said vessel propulsion means with joy stick means.
 7. A method of effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said method comprising: supporting a pipeline from said floating vessel means so that, an upper portion is supported from said floating vessel means, and a generally submerged portion, connected with said upper portion, extends downwardly to said submerged surface; at least periodically, detecting at least an indication of a vector component of tension exerted on said pipeline from said floating vessel means; supporting a portion of said generally submerged portion of said pipeline with generally submerged buoyant pontoon means; detecting a side elevational profile defined by said buoyant pontoon means; detecting generally vertical interaction between said buoyant pontoon means and said generally submerged portion of said pipeline; detecting generally lateral interaction between said buoyant pontoon means and said generally submerged portion of said pipeline, and adjusting a positional relationship between said buoyant pontoon means and said generally submerged portion of said pipeline in response to said detecting.
 8. Apparatus for effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said apparatus comprising: support means operable to support a pipeline from aid floating vessel means, said support means including, means operable to support an upper portion of said pipeline from said floating vessel means, with a generally submerged portion of said pipeline, connected with said upper portion, extending downwardly to said submerged surface; first detecting means operable, at least periodically, to detect at least an indication of a vector component of tension exerted on said pipeline from said floating vessel means; second detecting means operable, at least periodically, to detect at least an indication of a vector component of force interacting laterally between said floating vessel means and said pipeline and directed generally transversely of said pipeline; third detecting means operable, at least periodically, to detect at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means; digital processing means operable to digitally process said indication of tension exerted on said pipeline from said floating vessel means, indication of force interacting laterally between said floating vessel means and said pipeline, and indication of the position of said floating vessel means relative to a desired course of movement in accordance with a predetermined digital computer program; vessel propulsion unit control means operable, in response to said digItal processing of said indications of tension and interacting laterally directed force and said detecting of said indication of floating vessel means position, to adjust the thrust effect of said vessel propulsion units to tend to maintain tension exerted on said pipeline generally within a predetermined tension range, adjust the thrust effect of said vessel propulsion units to effect a movement of said floating vessel means tending to maintain said interacting laterally directed force generally within a predetermined force range, and adjust the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means generally on a desired course; means including and responsive to said digital processing means operable to effect said adjusting of the thrust effect of said vessel propulsion units to effect a movement of said floating vessel means tending to maintain said interacting laterally directed force within a predetermined force range as a matter of first priority in relation to thrust available from said vessel propulsion units; means including and responsive to said digital processing means operable to effect said adjusting of the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means on said desired course as a matter of second priority in relation to, and to the extent permitted by, thrust available from said vessel propulsion units; and manual input means operable during said laying of said pipeline to incorporate in said digital computer program digital processing data which is independent of said detected indications of tension, interacting laterally directed force, and position of said floating vessel means, and which relates to at least one of said predetermined tension range, said predetermined range of interacting laterally directed force, and said desired course of movement of said floating vessel means.
 9. An apparatus, as described in claim 8, for effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, wherein said support means includes: clamping means operable, periodically, to grip said upper portion of said pipeline so as to substantially prevent a segment of said upper portion from moving downwardly toward said generally submerged portion; yieldable, tensioning means, operable periodically and alternately with said clamping means, to feed segments of said upper portion of said pipeline generally toward said generally submerged portion of said pipeline while concurrently imparting a series of longitudinally spaced tensioning forces to said upper portion of said pipeline, which forces are operable to continuously bias said upper portion of said pipeline in a direction tending to impart tension to said generally submerged portion of said pipeline; said tensioning means including pneumatically inflated, rotary tires operable to remain continuously in biasing engagement with said pipeline substantially independent of the rate of floating vessel means movement and substantially independent of the direction of relative movement between said floating vessel means and said generally submerged portion of said pipeline; said rotary tires being operable to cradle said upper portion of said pipeline to prevent lateral displacement thereof; means operable during said gripping of said upper portion by said clamping means to impart a level of tension from said floating vessel means, through said support means, and to said generally submerged portion of said pipeline at a tension level substantially above that maintained during said feeding of pipeline segments so as to tend to maintain the level of tension imparted to said generally submerged portion of said pipeline during said gripping generally within a tension range which accommodates deviations in tension resulting from environmental forces acting on said floating vessel meAns without deviating from a predetermined tension range; and means operable, with said clamping means disengaged from gripping engagement with said pipeline, to cause said tensioning means to reduce said tension level and thereby cause said feeding of pipeline segments.
 10. An apparatus, as described in claim 8, for effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means wherein said third detecting means which is operable, at least periodically, to detect at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means, includes: satellite responsive navigation means operable to at least periodically determine the location of said floating vessel means with reference to an orbiting satellite orbiting the earth; and sonar beacon responsive navigation means operable, at least between the periodic determining of floating vessel means position with reference to said orbiting satellite, to extrapolate the position of said floating vessel means with reference to a generally fixedly positioned and submerged navigation station.
 11. Apparatus for effecting the laying of a pipeline on a submerged surface from vessel means including a plurality of vessel propulsion units, said apparatus comprising: support means operable to support a pipeline from said floating vessel means, said support means including, means operable to support an upper portion of said pipeline from said floating vessel means, with a generally submerged portion of said pipeline, connected with said upper portion, extending downwardly to said submerged surface; said support means including, clamping means operable, periodically, to grip said upper portion of said pipeline so as to substantially prevent a segment of said upper portion from moving downwardly toward said generally submerged portion, yieldable tensioning means, operable periodically and alternately with said clamping means, to feed segments to said upper portion of said pipeline generally toward submerged portion of said pipeline, said clamping means being operable, during said gripping of said pipeline, to accommodate deviations in pipeline tension resulting from environmental forces acting on said floating vessel means without causing said pipeline tension to substantially deviate from a predetermined tension range; said tensioning means being operable, with said clamping means disengaged from gripping engagement with said pipeline, to reduce tension imparted to said pipeline and thereby cause said feeding of segments; first detecting means operable, at least periodically, to detect at least an indication of a vector component of tension exerted on said submerged portion of said pipeline from said floating vessel means; second detecting means operable, at least periodically, to detect at least an indication of a vector component of generally horizontally directed force interacting laterally between said floating vessel means and said submerged portion of said pipeline and directed generally transversely of said pipeline; third detecting means operable, at least periodically, to detect at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means, said third detecting means including, satellite responsive navigation means operable to at least periodically determine the location of said floating vessel means with reference to an orbiting satellite orbiting the earth, and sonar beacon responsive navigation means operable, at least between the periodic determining of floating vessel means position with reference to said orbiting satellite, to extrapolate the position of said floating vessel means with reference to a generally fixedly positioned and submerged navigation station; vessel propulsion unit control means operable, in response to said detecting of said Indications of tension and interacting laterally directed force and said detecting of said indication of floating vessel means position, as a matter of first priority, to adjust the thrust effect of said vessel propulsion units to tend to maintain tension exerted on said generally submerged portion of said pipeline generally within a predetermined tension range, and to adjust the thrust effect of said vessel propulsion units to effect a turning movement of said floating vessel means tending to maintain said interacting laterally directed force within a predetermined force range, and as a matter of second priority, to adjust the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means on a desired course; and vessel propulsion unit thrust allocation means included in said control means and operable to effect said adjusting of the thrust effect of said vessel propulsion units, tending to maintain the tension exerted on said submerged portion of said pipeline generally within a predetermined tension range, so as to tend to maintain the deviation in thrust level between said vessel propulsion units within a predetermined condition of balance, effect said adjusting of the thrust effect of said vessel propulsion units, tending to maintain interacting lateral force between said floating vessel means and said submerged portion of said pipeline generally within a predetermined force range, by adjusting the thrust effect of pairs of vessel propulsion units so as to tend to minimize translation of said floating vessel means and so as to tend to maintain the deviation in thrust level between said vessel propulsion units within said predetermined condition of balance, and effect said adjusting of the thrust effect of said vessel propulsion units, tending to maintain said floating vessel means generally on a desired course, so as to tend to maintain the deviation in thrust level between said vessel propulsion units within said predetermined condition of balance.
 12. Apparatus for effecting the laying of a pipeline on a submerged surface from vessel means including a plurality of vessel propulsion units, said apparatus comprising: support means operable to support a pipeline from said floating vessel means, said support means including, means operable to support an upper portion of said pipeline from said floating vessel means, with a generally submerged portion of said pipeline connected with said upper portion, extending downwardly to said submerged surface; said support means including, clamping means operable, periodically, to grip said upper portion of said pipeline so as to substantially prevent a segment of said upper portion from moving downwardly toward said generally submerged portion, yieldable, tensioning means, operable periodically and alternately with said clamping means, to feed segments of said upper portion of said pipeline generally toward said generally submerged portion of said pipeline while concurrently imparting a series of longitudinally spaced tensioning forces to said upper portion of said pipeline, which forces are operable to continuously bias said upper portion of said pipeline in a direction tending to impart tension to said generally submerged portion of said pipeline, said tensioning means including pneumatically inflated, rotary tires operable to remain continuously in biasing engagement with said pipeline substantially independent of the rate of floating vessel means movement and substantially independent of the direction of relative movement between said floating vessel means and said generally submerged portion of said pipeline, said rotary tires being operable to cradle said upper portion of said pipeline to prevent lateral displacement thereof, means operable during said gripping of said upper portion by said clamping means to impart a level of tension from said floating vessel means, through said support means, and to said generally submerged portion of said pipeline at a tension level substantially above that maintained during said feeding of pipeline segments so as to tend to maintain the level of tension imparted to said generally submerged portion of said pipeline during said gripping generally within a tension range which accommodates deviations in tension resulting from environmental forces acting on said floating vessel means without substantially deviating from a predetermined tension range, and means operable, with said clamping means disengaged from gripping engagement with said pipeline to cause said tensioning means to reduce said tension level and thereby cause said feeding of pipeline segments; first detecting means operable, at least periodically, at a first detection frequency, and concurrently with said gripping, to detect at least an indication of a vector component of tension exerted on said submerged portion of said pipeline from said floating vessel means; second detecting means operable, at least periodically, at a second detection frequency equal to or less than said first detection frequency, and concurrently with said gripping, to detect at least an indication of a vector component of generally horizontally directed force interacting laterally between said floating vessel means and said submerged portion of said pipeline and directed generally transversely of said pipeline; third detecting means operable, at least periodically, at a third detection frequency equal to or less than said second detection frequency, and concurrently with said gripping, to detect at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means, said third detecting means including, satellite responsive navigation means operable to at least periodically determine the location of said floating vessel means with reference to an orbiting satellite orbiting the earth, sonar beacon responsive navigation means operable, at least between the periodic determining of floating vessel means position with reference to said orbiting satellite and concurrent with said gripping, to determine the position of said floating vessel means with reference to a generally fixedly positioned and submerged sonar beacon means, and means operable, with general reference to said periodically determined locations of said floating vessel means, to extrapolate the position of said floating vessel means with reference to said sonar beacon means, vessel propulsion unit control means operable, in response to said detecting of said indications of tension and interacting laterally directed force and said detecting of said indication of floating vessel means position, as a matter of first priority priority; to adjust the thrust effect of said vessel propulsion units to tend to maintain tension exerted on said generally submerged portion of said pipeline generally within a predetermined tension range, and to adjust the thrust effect of said vessel propulsion units to effect a turning movement of said floating vessel means tending to maintain said interacting laterally directed force within a predetermined force range, and as a matter of second priority, to adjust the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means on a desired course; vessel propulsion unit thrust allocation means included in said control means and operable to effect said adjusting of the thrust effect of said vessel propulsion units, tending to maintain the tension exerted on said submerged portion of said pipeline generally within a predetermined tension range, so as to tend to maintain the deviation in thrust level between said vessel propulsion units within a predetermined condition of balance, effect said adjusting of the thrust effect of said vessel propulsion units, tending to maintain interacting lateral force between said floAting vessel means and said submerged portion of said pipeline generally within a predetermined force range, by adjusting the thrust effect of pairs of vessel propulsion units so as to tend to minimize translation of said floating vessel means and so as to tend to maintain the deviation in thrust level between said vessel propulsion units within said predetermined condition of balance, and effect said adjusting of the thrust effect of said vessel propulsion units, tending to maintain said floating vessel means generally on a desired course, so as to tend to maintain the deviation in thrust level between said vessel propulsion units within said predetermined condition of balance; and said vessel propulsion unit control means further including thrust variation scheduling means operable to effect said adjusting of said thrust effects of said vessel propulsion units tending to maintain the tension exerted on said submerged portion of said pipeline generally with a predetermined range, tending to maintain interacting lateral force between said floating vessel means and said submerged portion of said pipeline generally within a predetermined force range, and tending to maintain said floating vessel means generally on a desired course, so that at least on a cyclic basis, a plurality of said thrust effects are generally simultaneously adjusted.
 13. Apparatus for effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said apparatus comprising: support means operable to support a pipeline from said floating vessel means, said support means including, means operable to support an upper portion of said pipeline from said floating vessel means, with a generally submerged portion of said pipeline, connected with said upper portion, extending downwardly to said submerged surface; said means operable to support an upper portion of said pipeline including clamping means operable, periodically, to grip said upper portion of said pipeline so as to substantially prevent a segment of said upper portion from moving downwardly toward said generally submerged portion, and yieldable tensioning means, operable periodically and alternately with said clamping means, to feed segments of said upper portion of said pipeline generally toward submerged portion of said pipeline; said yieldable tensioning means being operable to impart yieldable tension to side means of said upper portion of said pipeline on said floating vessel means; said yieldable tensioning means including tension adjusting means operable to reduce the level of tension imparted to said side means of said upper portion of said pipeline, substantially independent of force exerted on said vessel means by said vessel propulsion means, with said reducing of tension being operable to cause feeding of a segment of said pipeline from said upper portion generally toward said generally submerged portion; said tension adjusting means being further operable to increase the level of tension imparted to said side means of said upper portion of said pipeline, substantially independent of force exerted on said vessel means by said vessel propulsion means, with said increasing of tension being operable to substantially prevent the feeding of further segments of said pipeline from said upper portion of said pipeline generally toward said generally submerged portion; and means operable during said gripping of said upper portion by said clamping means to impart a level of tension from said floating vessel means, through said support means, and to said generally submerged portion of said pipeline at a tension level substantially above that maintained during said feeding of pipeline segments so as to tend to maintain the level of tension imparted to said generally submerged portion of said pipeline during said gripping generally within a tension range which accommodates deviations in tension resulting from environmental forces, including wave acTion, acting on said floating vessel means without deviating from a predetermined tension range.
 14. Apparatus for effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said apparatus comprising: support means operable to support a pipeline from said floating vessel means, said support means including, means operable to support an upper portion of said pipeline from said floating vessel means, with a generally submerged portion of said pipeline, connected with said upper portion, extending downwardly to said submerged surface; detecting means operable to detect a deviation in the condition of said pipeline; and digital processing means operable to digitally process said indication of a deviation in the condition of said pipeline in accordance with a predetermined digital computer program; control means operable in response to said digital processing to adjust the thrust effect of said vessel propulsion means in an effort to tend to relieve said detected deviation, with said adjustment in thrust effect including a first component which is related directly to and tends to offset, said detected condition of deviation, a second component which tends to offset a bias condition tending to produce said deviation, and a third component which tends to offset the rate at which said deviation occurred; means including and responsive to said digital processing means operable to effect said adjusting of the thrust effect of said vessel propulsion means to tend to relieve said detected deviation in the condition of said pipeline as a matter of first priority in relation to thrust available from said vessel propulsion means; means including and responsive to said digital processing means operable to effect an adjusting of the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means on a desired course as a matter of second priority in relation to, and to the extent permitted by, thrust available from said vessel propulsion means; and manual input means operable during said laying of said pipeline to incorporate in said digital computer program digital processing data which is independent of said detected deviation in the condition of said pipeline and which relates to said pipeline condition.
 15. Apparatus for effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said apparatus comprising: support means operable to support a pipeline from said floating vessel means, said support means including, means operable to support an upper portion of said pipeline from said floating vessel means, with a generally submerged portion of said pipeline, connected with said upper portion, extending downwardly to said submerged surface; first detecting means operable, at least periodically, to detect at least an indication of a vector component of tension exerted on said pipeline from said floating vessel means; second detecting means operable, at least periodically, to detect at least an indication of a vector component of generally horizontally directed force interacting laterally between said floating vessel means and said pipeline and directed generally transversely of said pipeline; third detecting means operable, at least periodically, to detect at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means; vessel propulsion unit control means operable, in response to said detecting of indications of tension and interacting laterally directed force and said detecting of said indication of floating vessel means position, to adjust the thrust effect of said vessel propulsion units to tend to maintain tension exerted on said pipeline generally within a predetermined tension range, adjust the thrust effect of said vessel propUlsion units to effect a turning movement of said floating vessel means tending to maintain said interacting laterally directed force generally within a predetermined force range, and adjust the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means generally on a desired course; display means operable to display, on said vessel means, a visual representation of thrust azimuth means of said vessel propulsion means; and joy-stick means operable to operate said vessel propulsion means.
 16. An apparatus for effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said apparatus comprising: support means operable to support a pipeline from said floating vessel means, said support means including, means operable to support an upper portion of said pipeline from said floating vessel means, with a generally submerged portion of said pipeline, connected with said upper portion, extending downwardly to said submerged surface; tension detecting means operable, at least periodically, to detect at least an indication of a vector component of tension exerted on said pipeline from said floating vessel means; said support means including buoyant and generally submerged pontoon means operable to support a portion of said generally submerged portion of said pipeline; attitude detecting means operable to detect a side elevational profile defined by said buoyant pontoon means; generally vertical load detecting means operable to detect generally vertical interaction between said buoyant pontoon means and said generally submerged portion of said pipeline; lateral load detecting means operable to detect generally lateral interaction between said buoyant pontoon means and said generally submerged portion of said pipeline; and control means operable to adjust a positional relationship between said buoyant pontoon means and said generally submerged portion of said pipeline in response to said detecting.
 17. A method of effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said method comprising: supporting a pipeline from said floating vessel means so that an upper portion is supported from said floating vessel means, and a generally submerged portion, connected with said upper portion, extends downwardly to said submerged surface; said supporting of said upper portion of said pipeline being effected by: periodically gripping said upper portion of said pipeline so as to substantially prevent a segment of said upper portion from moving downwardly toward said generally submerged portion, periodically and alternately with said gripping of said upper portion of said pipeline, feeding segments of said upper portion of said pipeline generally toward said generally submerged portion of said pipeline while concurrently imparting tensioning force to said upper portion of said pipeline operable to continuously bias said upper portion of said pipeline in a direction tending to impart tension to said generally submerged portion of said pipeline, with said biasing remaining continuously in effect, substantially independent of the rate of floating vessel means movement and substantially independent of the direction of relative movement between said floating vessel means and said generally submerged portion of said pipeline, concurrently with said gripping, cradling said upper portion of said pipeline to prevent lateral displacement thereof; during said gripping of said upper portion of said pipeline, adding pipeline segments to said upper portion and providing a level of tension imparted from said floating vessel means to said generally submerged portion of said pipeline at a tension level substantially above that maintained during said feeding of pipeline segments so as to tend to maintain the level of tension imparted to said generally subMerged portion of said pipeline during said gripping generally within a tension range which accommodates deviations in tension resulting from environmental forces acting on said floating vessel means without deviating from a predetermined tension range; intermittently with said gripping, reducing tension level and thereby cause said feeding of pipeline segments; at least periodically detecting at least an indication of a vector component of tension exerted on said pipeline from said floating vessel means; at least periodically detecting at least an indication of a vector component of generally horizontally directed force interacting laterally between said floating vessel means and said pipeline and directed generally transversely of said pipeline; at least periodically, detecting at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means; and in response to said detecting of said indications of tension and interacting laterally directed force and said detecting of said indication of floating vessel means position, adjusting the thrust effect of said vessel propulsion units to tend to maintain tension exerted on said pipeline generally within a predetermined tension range, adjusting the thrust effect of said vessel propulsion units to effect a turning movement of said floating vessel means tending to maintain said interacting laterally directed force generally within a predetermined force range, and adjusting the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means generally on a desired course.
 18. A method of effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said method comprising: supporting a pipeline from said floating vessel means so that an upper portion is supported from said floating vessel means, and a generally submerged portion, connected with said upper portion, extends downwardly to said submerged surface; at least periodically, detecting at least an indication of a vector component of tension exerted on said pipeline from said floating vessel means, at least periodically, detecting at least in indication of a vector component of generally horizontally directed force interacting laterally between said floating vessel means and said pipeline and directed generally transversely of said pipeline; at least periodically, detecting at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means; and said detecting of at least an indication of the position of said floating vessel means relative to a desired course of movement of said floating vessel means being effected by periodically determining the location of said floating vessel means with reference to an orbiting satellite orbiting about the earth, between the periodic determining of floating vessel means position with reference to said orbiting satellite, extrapolating the position of said floating vessel means with reference to a generally fixedly positioned and submerged navigation station, and periodically repositioning said submerged navigation station along said course of movement of said vessel means; in response to said detecting of said indications of tension and interacting laterally directed force and said detecting of said indication of floating vessel means position, adjusting the thrust effect of said vessel propulsion units to tend to maintain tension exerted on said pipeline generally within a predetermined tension range, adjusting the thrust effect of said vessel propulsion units to effect a turning movement of said floating vessel means tending to maintain said interacting laterally directed force generally within a predetermined force range, and adjusting the thrust effect of said vessel propulsion units to tend to maintain the position of said floating vessel means generally on a desired course.
 19. An apparatus as described in claim 8 for effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, said apparatus further comprising: means operable, at least at times, to simultaneously effect all of said adjustings of the thrust effects of said vessel propulsion units so as to tend to simultaneously maintain tension exerted on said pipeline generally within said predetermined tension range, maintain said interacting laterally directed force generally within said predetermined force range, and maintain the position of said floating vessel means generally on said desired course; and means operable to induce said adjustings of the thrust effects of said vessel propulsion units at values derived at least in part from a magnitude of deviation, and a bias tending to produce said deviation in relation to each of predetermined values of tension in said pipeline, force interacting laterally between said pipeline and said floating vessel means, and floating vessel means position.
 20. A method, as described in claim 1, for effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means, wherein: said supporting of said upper portion of said pipeline is effected by periodically gripping said upper portion of said pipeline with clamping means so as to substantially prevent a segment of said upper portion from moving downwardly toward said generally submerged portion, and periodically and alternately with said gripping of said upper portion of said pipeline, utilizing tensioning means to feed segments of said upper portion of said pipeline generally toward submerged portion of said pipeline; during said feeding of pipeline segments yieldable tension is imparted with said tensioning means to side means of said upper portion of said pipeline on said floating vessel means; feeding of pipeline segments is initiated by reducing the level of tension imparted to said side means of said upper portion of said pipeline by said tensioning means, substantially independent of force exerted on said vessel means by said vessel propulsion means, with said reducing of tension being operable to cause feeding of a segment of said pipeline from said upper portion generally toward said generally submerged portion; and the level of tension imparted to said side means of said upper portion of said pipeline by said tensioning means is increased during said feeding of pipeline segments, substantially independent of force exerted on said vessel means by said vessel propulsion means, with said increasing of tension being operable to substantially prevent the feeding of further segments of said pipeline from said upper portion of said pipeline generally toward said generally submerged portion; and during said gripping of said upper portion of said pipeline with clamping means, pipeline segments are added to said upper portion of said pipeline and a level of tension is imparted from said floating vessel means through said support means to said generally submerged portion of said pipeline at a tension level substantially above that maintained during said feeding of pipeline segments so as to tend to maintain the level of tension imparted to said generally submerged portion of said pipeline during said gripping generally within a tension range which accommodates deviations in tension resulting from environmental forces, including wave action, acting on said floating vessel means without deviating from a predetermined tension range.
 21. An apparatus as described in claim 8 for effecting the laying of a pipeline on a submerged surface from vessel means including vessel propulsion means wherein: said support means includes clamping means operable, periodically, to grip said upper portion of said pipeline so as to substantiAlly prevent a segment of said upper portion from moving downwardly toward said generally submerged portion, and yieldable tensioning means, operable periodically and alternately with said clamping means, to feed segments of said upper portion of said pipeline generally toward submerged portion of said pipeline; said yieldable tensioning means is operable to impart yieldable tension to side means of said upper portion of said pipeline on said floating vessel means; said yieldable tensioning means includes tension adjusting means operable to reduce the level of tension imparted to said side means of said upper portion of said pipeline, substantially independent of force exerted on said vessel means by said vessel propulsion means, with said reducing of tension being operable to cause feeding of a segment of said pipeline from said upper portion generally toward said generally submerged portion; said tension adjusting means is further operable to increase the level of tension imparted to said side means of said upper portion of said pipeline, substantially independent of force exerted on said vessel means by said vessel propulsion means, with said increasing of tension being operable to substantially prevent the feeding of further segments of said pipeline from said upper portion of said pipeline generally toward said generally submerged portion; and said support means further includes means operable during said gripping of said upper portion by said clamping means to impart a level of tension from said floating vessel means, through said support means, and to said generally submerged portion of said pipeline at a tension level substantially above that maintained during said feeding of pipeline segments so as to tend to maintain the level of tension imparted to said generally submerged portion of said pipeline during said gripping generally within a tension range which accommodates deviations in tension resulting from environmental forces, including wave action, acting on said floating vessel means without deviating from a predetermined tension range. 